Influence of argon pollution on the weld surface morphology

•Surface morphology of weld area depending on the argon pollution.•Influence of argon pollution on the waviness of surface.•Subzones distribution on the surface from the metrological point of view.•Topography parameters for all subzones.•Surface morphology characterization depending on argon pollution.

In this paper the surfaces of butt welded joints in steel tubes were analyzed using an optical 3D measurement system to determine the morphology and topographic parameters. It was established that pollution of the argon shield gas with oxygen did not influence the width of the heat-affected zone. However, the composition of the shield gas significantly influenced the surface asymmetry, Ssk, and its inclination Sku. The measurement of these parameters enabled the selection of a higher quality surface, which was visually proven by the reduction in discoloration of the surface of the weld joint. High quality surfaces eliminate a potential habitat for bacteria and a future source of corrosion as well as providing less resistance to fluid flow.

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